Schooling fish
Buy the group, or do not buy the fish.
Tetras, rasboras, danios, white clouds, and others that want six or more of their own kind. Two neons in a 10-gallon are decoration, not a school.
Six is the floor for most tetras and rasboras. Ten looks like a school in a 20 long. Two of a species “to see if I like them” is how you get nervous fish hugging the back glass.
One school per tank in a 20. Two competing midwater groups want more length than a 10 or a 20 high.
Skip
- A pair of neons in a 10 next to a betta.
- Mixing five species at two each because the bags were on sale.
Run compatibility on the mix, then stocking with adult sizes.
Neon Tetra
Paracheirodon innesi
The default midwater school.
A group of six-plus fills the middle of a 20 long so the tank does not look empty.
Cardinal Tetra
Paracheirodon axelrodi
A showier neon that wants better water.
Same schooling job as neons, with a full-body red stripe.
Ember Tetra
Hyphessobrycon amandae
Nano school for a planted 10.
Actually fits a 10-gallon as a group.
Harlequin Rasbora
Trigonostigma heteromorpha
Calm midwater school for a 20 long.
Less nippy than barbs, less fragile than cardinals.
Zebra Danio
Danio rerio
Fast top-water school. Hardy, slightly chaotic.
Tolerates cooler rooms than tetras.
White Cloud Mountain Minnow
Tanichthys albonubes
The honest no-heater school.
Lives in the mid-60s without a heater if the room stays cool.
Cherry Barb
Puntius titteya
A peaceful barb for a planted 20.
Schooling color without tiger-barb nipping — if you keep six-plus.
Tiger Barb
Puntigrus tetrazona
Active school that nips unless the school is large.
Lots of motion in a 29-plus.
Discus
Symphysodon spp.
Show fish with show requirements.
A planted discus tank is the look people steal for photos.
Corydoras Catfish
Corydoras spp.
The correct bottom crew for a community.
Sift sand so leftover food and mulm do not sit and rot.